Electro-photographic image forming apparatuses generally operate to form an electrostatic latent image by scanning light beams on the surface of a drum using a light scanning unit, develop the electrostatic latent image using a developing agent (e.g., toner) to generate a developed image, transfer the developed image onto a printing medium, and fuse the transferred image to the printing medium to form an image.
The light scanning unit of a conventional image forming apparatus typically uses a polygon mirror driven with, e.g., a spindle motor. A new mechanism to replace the spindle motor and the polygon mirror may be needed to overcome limitations in the velocity of the polygon mirror, to remove noise generated by the spindle motor during a high velocity operation, and/or to reduce the size of the light scanning unit. The light scanning unit can use a micro electro-mechanical system (MEMS) structure that allows for bidirectional and high-velocity scanning. Moreover, the light scanning unit can be made using semiconductor processes such that it has a very small size. Thus, the light scanning unit can be made using a MEMS structure instead of a polygon mirror. Because a light scanning unit scans multiple light beams to form a color image, using a MEMS-type beam deflector can be advantageous in that the MEMS-type beam deflector can rotate and vibrate a double-sided mirror and can scan multiple light beams concurrently.